Merge pull request #6 from ruby-syntax-tree/dependabot/bundler/simplecov-0.22.0

Bump simplecov from 0.21.2 to 0.22.0

Author: github-actions[bot]

Gemfile.lock

@@ -9,7 +9,7 @@ GEM
     docile (1.4.0)
     power_assert (2.0.2)
     rake (13.0.6)
-    simplecov (0.21.2)
+    simplecov (0.22.0)
       docile (~> 1.1)
       simplecov-html (~> 0.11)
       simplecov_json_formatter (~> 0.1)